Pause the game, then press the following button combinations:

1. UP + (A) + (B) + (C)
2. RIGHT + (A)
3. DOWN + (B)
4. LEFT + (C)

You will hear a sound if you entered the code correctly. Unpause the game, and you will have all but one of the ship pieces collected. The last piece will always be located on the next level.

At the top right of the map on level 1, there is a hidden island with a load of preasents for the taking. You will need rocket skates, an inner-tube or icarus wings to get there.

Sneak up on Santa Claus before he takes off and he'll give you a few presents.

On Level 1, on the bottom left side, there is a small hole that leads to level 0, which has hula dancers in a tub and a lemomade man who gives you another life.